Answer: Briefly, identify the group with a flag, then create a new dataset using the flag to select members of the new set.-- First, why get rid of them? There's no reason to, unless the size of the database is slowing your system down. --

Create a flag with values NY. The purpose of the flag is to mark people to keep; N or No is the default.

Use List of People (LOP) reports with secondary output, Focus Groups and manual changes to set the flag to Y for people you want to keep.

You might also want an LOP report whose secondary output resets the flag to the default.

Once you have the people set the way you want them, run a final LOP report. Set your flag equal to Y and Secondary Output of creating a new data set. The new data set will have the people you want and the others will be gone.